Ontogenetic colour change in Oreophryne ezra (Anura: Microhylidae) reflects an unusual shift from conspicuousness to crypsis but not in toxicity

Ontogenetic colour change (OCC) may signal a switch in defensive strategies across development. Commonly, juveniles use cryptic colours and transition to conspicuous coloration as adults. Extensive theoretical and empirical work suggest such a transition is more likely than the converse. Oreophryne ezra, a newly discovered frog from New Guinea, however, undergoes OCC that belies expectations. We investigated the notion juveniles are aposematic while the adults use crypsis. We quantified the extent of conspicuousness of O. ezra across life stages using spectrophotometry and models of avian vision; and analysed skin extracts for the presence of toxic alkaloids. As predicted, the juvenile colour patterns were estimated to be conspicuous to likely predators against the frogs natural viewing backgrounds, while adults consistently fell below the threshold of discriminability. However, we discovered no alkaloids in either juveniles or adults. This suggests the juveniles use alternative defensive chemicals, or the colour pattern has an alternative origin – to which we offer the hypothesis that juvenile frogs may be Batesian mimics of a synoptic species of weevil. This study highlights the potential for this system, and others like it, to inform our understanding of the adaptive significance of OCC and the selective drivers for different anti-predatory strategies

The unusual occurrence of green algal balls of <i>Chaetomorpha linum</i> on a beach in Sydney, Australia.

In spring 2014, thousands of green algal balls were washed up at Dee Why Beach, Sydney, New South Wales, Australia. Reports of algal balls are uncommon in marine systems, and mass strandings on beaches are even more rare, sparking both public and scientific interest. We identified the algal masses as Chaetomorpha linum by using light microscopy and DNA sequencing. We characterize the size and composition of the balls from Dee Why Beach and compare them to previous records of marine algal balls. We describe the environmental conditions that could explain their appearance, given the ecophysiology of C. linum

Escape distance and escape latency following simulated rapid bird attacks in an Andean lizard, Phymaturus williamsi

Predatory birds represent the greatest risk for many lizard species. However, little is known about the functional relationship between the escape distance and escape latency of lizards during a rapid bird attack. We hypothesised that escape latency and distance in the Andean lizard species Phymaturus williamsi would increase proportionally, but vary according to the means of escape. Over a three-year period we observed seven types of antipredatory behaviour in 98% P. williamsi lizards on simulated predatory bird attacks. Escape distance and latency were positively correlated. 65% of lizards emerged from their refuge within 2 min of an attack. All of these behaviours were positively correlated with escape latency and distance, although we found the former to be more precise. This study contributes to a better understanding of the general antipredatory behaviour in this species of Andean lizard, and will assist in future decisions concerning its conservation.Fil: Fava, Gustavo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Acosta, Juan Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentin

Impact of cropland management on invertebrate richness and abundance in agroforestry systems in Bali, Indonesia

The intensive management of cropland refers to a reduction in habitat complexity (i.e., shade tree cover, tree species richness, crop species richness) to gain more profits. This usually entails a decrease in biodiversity, but agroforestry systems have been shown to provide a solution to the need for profits while maintaining biodiversity and ecosystem services. Invertebrates are important bioindicators since they are not just affected by a decrease in habitat complexity; they are also key for the maintenance of ecosystems given their ecological roles. We aimed to understand how agricultural intensification impacted invertebrate abundance and richness in an agroforestry system in Bali, Indonesia. We set up 53 × 25 m2 plots and collected data via pitfall and pan traps. We linked those data to vegetation data (canopy cover, tree species richness, crop species richness), habitat type (rustic vs. polyculture), and productivity. Overall, we found that the abundance and richness of invertebrate taxa were positively influenced by increasing canopy cover and crop and tree species richness. This supports the habitat heterogeneity hypothesis, which indicates that increased habitat complexity promotes higher invertebrate species richness and abundance. The abundance and richness of certain invertebrate taxa, including agents of biocontrol, were shown to increase in plots with higher yields, thus solidifying the important role of invertebrate communities in the provision of ecosystem services. Harvesting crops from complex agroforestry systems ensures a sustainable income for local communities as well as habitats for invertebrates

Sexual dimorphism in the Arachnid orders.

Sexual differences in size and shape are common across the animal kingdom. The study of sexual dimorphism (SD) can provide insight into the sexual- and natural-selection pressures experienced by males and females in different species. Arachnids are diverse, comprising over 100,000 species, and exhibit some of the more extreme forms of SD in the animal kingdom, with the males and females of some species differing dramatically in body shape and/or size. Despite this, research on arachnid SD has primarily focused on specific clades as opposed to observing traits across arachnid orders, the smallest of which have received comparatively little attention. This review provides an overview of the research to date on the trends and potential evolutionary drivers for SD and sexual size dimorphism (SSD) in individual arachnid orders, and across arachnids as a whole. The most common trends across Arachnida are female-biased SSD in total body size, male-biased SSD in relative leg length and SD in pedipalp length and shape. However, the evolution of sexually dimorphic traits within the group is difficult to elucidate due to uncertainty in arachnid phylogenetic relationships. Based on the dataset we have gathered here, we highlight gaps in our current understanding and suggest areas for future research

Luring

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Comparative trichome morphology in feather-legged assassin bugs (Insecta: Heteroptera: Reduviidae: Holoptilinae)

The trichome in ant-feeding Holoptilinae (Insecta: Heteroptera: Reduviidae) comprises remarkable modifications of abdominal sternites 2 and 3. It has been hypothesized that this structure plays a role in attracting and drugging ants. In the present study the trichome of 14 species of Holoptilini, comprising 11 species of Ptilocnemus Westwood and representatives of three additional genera of Holoptilini, is examined using scanning electron and light microscopy. The astoundingly diverse species-level modifications of sternites and vestiture are described and primary homology hypotheses are proposed. The trichome provides species-specific diagnostic characters within Ptilocnemus and evidence for species-groups within the genus, but also for the sistergroup relationship of Ptilocnemus and Smiliopus Bergroth. The comparative morphology establishes a framework for investigations into systematics, functional morphology, and behavioral ecology of these myrmecophagous assassin bugs.17 page(s